Reamer expanding pilot



July 13 1926. v 1,592,166

I W. H. TURNER REMER EXPANDNG PILOT Filed April 2l, 1924 a \Q gm llllll Y head.

- of Figure 2.

Patented .idly 13, i926.

WARREN n. TURNER, on xaNsas CITY, Missounr, assisnon `Te THE yTURNER iraniana AND limitarne-rumana COMPANY, or KANSAS ci'rY, lilssouai, A coa- PORATION OF MISSOURI.

BEAMER EXPANDING PILOT.

Application filed April 21, 1924i. Serial No. 707,930.

,This invention relates to .expanding pilots for use in centering reamers and is designed more especially for use where it is desired to r'eam out two axially i alined spaced holes, for example, the wrist pin holes in a piston v`Heretofore, with centering guide located at the extreme end of the holes, it has been difficult to properly aline the reamer when commencing the reaming operation as the bit is free for more or less chattering.

The object of the invention, therefore, is to provide an expanding pilot which may be used in holes of varying diameter within certain limits and whichA will offer a firm and unyielding guide closely adjacent to the cutting elements of the reainer in all stages oflthel reaming operation, thus eifectually guarding against chattering and insuring holes of uniform diameter from end to end.

Another object is to produce a pilot of theI character mentioned which is adapted for use with the common and ordinary type of reamer now on the market and called the Critchley reamer, and which is of strong, durable, efcient and inexpensive constructionf lith the objects named in view, the in vention consists in certain novel and useful features of construction and organization of parts as hereinafterk described and claimed; and in order that it may be fully understood, reference is to be had to the accompanying drawing, in which Figure 1 is a side elevation of a tool enibodying the invention and illustrates in section a piston head in -the process of being reamed.

Figure 2 is a central longitudinal section thro-ugh the expanding pilot constituting the invention.

Figure 3 is a vsection on the line Ill-ill Figure 4 is an end view of the pilot.

ln the'said drawing, where like reference characters identify corresponding parts in all of the figures, 1 illustrates the shank of the ordinary type of reamer used in reaming out wrist pin holes in Vpiston heads, the body being threaded as at 2. Mounted in the threaded portion of the reainerl are the cutting or scraping bits 3 spaced apart by the rib members 4; of the threaded body. The reamer which is of the well-known Critchley type is complete .except that one of the nuts (it 'whereby the cutters are longitudinally adjusted and held, is omitted.

A tubular expansible pilot 5 having internal threads 6 and 7 at its opposite ends, is attached .to the end of the reainer 2 'by engaging it at the threaded end 6, and is screwedV home to maintain ,the bits in posi- Vtion and performs the function of the omitted nut 4a. Between the threaded ends 6 and 7, the pilot 5 is formed with a series of equi-spaced slits 8, dividing the body of the pilot into a series of sections 9 which may be expanded, as will hereinafter appear.

Fiach of the sections 9 is formed internally `and at a point substantially midway its length, with a substantially fil-shaped lug 10,. In order to apply pressure against thelugs 10 to expand the sections 9,`an expanding pin 11 has threaded engagement with the end 7 and isfori'ned at its extremity with a tapered portion 12 adapted to engage the faces of the lugs 10, and upon the inward movement of said pin, will apply outward force against the lugs and bring about the expansion of the sections 9 equally in all directions to properly fit in the holes to be reamed.

In order that the expansion pin 11 may be conveniently screwed into position, its 'extremity is formed with a suitable socket 13;

and in order to attach and detach the pilot from the end of the reamer, the end of said pilot is flattened slightly as at 14 on its opposite sides for convenience in gripping same with a wrench or the like.

In the operation of the device, the pilot is first slipped into the hole to be reamed and then is expanded by means of the pin 11 until it snugly engages the hole, it being noted in this connection that the external diameter of the expanded portion of the pilot is the same for substantially the length of the lugs and coincidental therewith, and then that it gradually tapers downward in opposite directions from said central portion. By reference to Figure 1, it will be seen, due to the fact the pilot is of substantially the same diameter coincidental with l the lugs, that it will properly center itself in both wrist pin holes and bridge the space between them after the reamer has commenced to act on the first hole, thus offering a firm bearing for the reamer and hold the same against chattering.

The pilot will maintain engagement with the wrist pin holes until the reamer has stabilized itselit in the second hole to such extent that it will be impossible for it to have any plarv and hence will engage and reain the second hole in pertect alinement with the first one.

With a reamer of this type, it will be possible by lirst litting it in the holes and then removing it, to obtain exact measurements ot' the holes by placing a micrometer on the pilot, something which cannot be accomplished with any pilot as 'liar as known, for use with the Critchley type of reamer.

From the above description it will be apparent that I have produced a device ot the character described which possesses all of the features of advantage Yl'orth as desirable. and while I have described and claimed the preferred embodiment ot the same, I reserve the right to make all changes properly falling within the spirit and scope of the appended claims.

l claim:

l. An expanding pilot comprising a tubular longitudinally-slotted member having solid ends and threaded at one ot its ends and provided, with internal lugs, said member being formed at its other end with internal threads adapted for engagement with a reamer, and means for applying force radially outward on said lugs and having threaded engagement with the iirst-nained threads ol said member.

2. An expanding pilot comprising a tubular longitudinally-slotted member having solid ends and threaded at one ol its ends and provided with internal lugs, said member being Yformed at its other end with internal threads adapted for engagement with a reanier to clamp the cutting blades thereof in position, and means engaging the first-named threaded end tor applying force radially outward on said lugs to eli'ect the exliiansion ot the pilot.

3. The combination with a reamer having longitudinall).Y adjustable bits and a threaded end, of a resilient tubular pilot threaded at its opposite ends and engaged at one end with the threaded end oit said reamer and at such end abutting and maintaining said bits in position, the slots of the pilot terminating short of the ends thereof, and, means for e.\'- panding the pilot intermediate its ends.

ln witness whereof I hereunto ai'lix my si gnature.

iVARREN H. TURNER. 

